Double jack plate



FIG. 1 is a rear elevational view of the double jack plate showing my new design;

FIG. 2 is a front elevational view;

FIG. 3 is the left side elevational view;

FIG. 4 is the right side elevational view;

FIG. 5 is a top plan view; and,

FIG. 6 is a bottom plan view. 

CLAIM The ornamental design for a double jack plate, as shown and described. 